Successful radiotherapy practice depends on the irradiation of tumours such that their destruction follows without unacceptable damage of the surrounding normal tissues. Until recently the accurate acquisition of data concerning the tumour anatomy lagged behind other developments in radiotherapy. Since the arrival of the CT scanner, these anatomical data can be displayed ideally for transmission into a computerised treatment planning system. The CT scan information concerning tumour location, irradiation volume and dosimetry was compared with results obtained using traditional planning methods. CT scanning proves to be an effective method for imaging normal and pathological anatomy. It provides quantitative, 3 dimensional demonstration of the tumour, its local and regional extension and its true relation to surrounding normal tissue. For the first time in the treatment planning process itself, CT scanning offers a sophistication of tumour localisation equal to the demands of treatment planning computers and supervoltage therapy capabilities. It has been incongruous in the past to use relatively precise and complex treatment algorithms when tumour localisation was, at best, just an indirect estimate. In order to assess the place of computed tomography in radiotherapy planning, the tumour target volumes are localised both be conventional techniques and with CT scanning under conditions simulating the radiotherapy. A comparison between the two methods has been made in a group of 205 patients with tumours at various sites. Firstly the diagnosis and staging is defined in order to localise the malignancy and decide the treatment policy. Those cases which are to be irradiated are then planned using the conventional simulator techniques and a computer plan of the radiotherapy dose distribution is produced.

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B.H.P. van der Werf-Messing , A.H. Tierie
Erasmus University Rotterdam
Erasmus MC: University Medical Center Rotterdam

Badcock, P.C. (1983, September 30). Computerised tomography in radiotherapy planning . Erasmus University Rotterdam. Retrieved from